travis: Explain why not publishing docs
travis: Explain why not publishing docs

It doesn't seem to be working even for the master branch

logcabin/logcabin,TigerZhang/logcabin,chaozh/logcabin,dankenigsberg/logcabin,logcabin/logcabin,tempbottle/logcabin,tempbottle/logcabin,gaoning777/logcabin,tempbottle/logcabin,tempbottle/logcabin,gaoning777/logcabin,gaoning777/logcabin,nhardt/logcabin,nhardt/logcabin,nhardt/logcabin,chaozh/logcabin,chaozh/logcabin,TigerZhang/logcabin,chaozh/logcabin,logcabin/logcabin,dankenigsberg/logcabin,dankenigsberg/logcabin,gaoning777/logcabin,nhardt/logcabin,dankenigsberg/logcabin,TigerZhang/logcabin,logcabin/logcabin,TigerZhang/logcabin